Product authentication is the manner whereby a legitimate product may be distinguished from a counterfeited fake designed to resemble the genuine article. Product authentication also plays a critical role in distinguishing diverted or “gray market” products, which are by definition legitimately manufactured products distributed into markets other than originally intended in violation of a contract, law or regulation. Closely linked to product authentication are “track and trace” of product movement in the supply chain from manufacturer to intermediary suppliers and retailers to end customers.
Authentication methods are also widely used as manner for providing secure access to sensitive areas or information, for example, using passwords, biometrics, or public-private key methods.
Further, product identification at the item level is desirable in cases where an individual instance of like products must be distinguished from all other instances of that product. A person's signature affixed to a document, whether done so manually or through digital processes, falls into this latter category.
Also useful is the authentication and identification of text in documents subject to changes. In general, any document of value is subject to changes for fraudulent purposes. Examples include prescriptions for controlled substances like narcotic analgesics, medical records, supply chain documents like customs forms and manifests, and academic records like transcripts, letters of recommendation, and diplomas.